1. Field of the Invention
The present invention relates to a method for cleaving a compound semiconductor substrate for laser diode or the like. In particular, the present invention relates to a method for manufacturing a semiconductor device capable of alleviating the divergence of cleavages from a desired cleavage line.
2. Background Art
A semiconductor substrate is formed from a sliced single crystal; the single crystal has a readily isolating cleavage plane. Therefore, when a substrate is cleaved, a scribe line is first formed on one side or both sides of the substrate along a cleavage plane using a diamond-point tool or the like. Directly under the scribe line, micro-cracks (minute cracks) are formed. Next, stress is applied to the substrate to open the micro-cracks along the cleaved plane. Thereby, the substrate can be separated while forming a cleaved plane having atomic-level smoothness (for example, refer to Japanese Patent Application Laid-Open No. 11-274653 (pages 2 to 3, FIGS. 3 to 8)).